Novel antiasthmatic agents with dual activities of thromboxane A2 synthetase inhibition and bronchodilation. 1. 2-[2-(1-imidazolyl)alkyl]- 1(2H)-phthalazinones

Article abstract of DOI:10.1021/jm00077a008

A number of 4-substituted 2-[ω-(1-imidazolyl)alkyl]-1(2H)-phthalazinones were synthesized in order to develop agents possessing both thromboxane A₂ synthetase inhibitory and bronchodilatory activities. The pharmacological evaluation of these compounds disclosed that they have both activities to various extents. Both activities were slightly dependent on the length of the 2-substituents and largely affected by the nature of the 4-substituents. Compounds bearing phenyl and thienyl groups exhibited relatively high and well-rounded activities. Among these compounds, 12j and 15f were found to be the most effective agents having well-rounded activities in vitro and in vivo. Introduction of a carboxyl group reduced both activities contrary to our expectation. 4-(3-Pyridyl)phthalazinone 18b was of particular interest because of unexpectedly high in vivo activities in spite of an absence of significant in vitro activities.